The resins used shall be a commercial
grade polyester and shall be evaluated as a laminate by test or determined by previous
service to be acceptable for the intended environment.The reinforcing material shall be a commercial grade of glass fiber
(continuous strand, chopped-strand, continuous mat and/or non-continuous mat) having a
coupling agent which will provide a suitable bond between the glass reinforcement material
resin.
The FRP laminate wall thickness shall very with the
wet well height to provide the aggregate strength necessary to meet the tensile and
flexural physical properties requirements. The wet well FRP wall laminate must be
designed to withstand wall collapse or buckling based on a hydrostatic
loading of 62.4
lbs. per cubic ft.; a saturated soil weight of 120 lbs, per cubic ft.; a soil modus of 700
lbs. per sq ft.; and, the pipe stiffness values as specified in ASTM D3753. The
wet well FRP laminate must be constructed to withstand or exceed two times the assumed
loading on any depth of the wet well.
The finished FRP laminate will have a Barcol
hardness of at least 90% of the resin manufacturer's specified hardness for the fully
cured resin. The Barcol hardness shall be the same for both interior and exterior
surfaces.
The wet well top flange shall have an outside
diameter at least 4" greater than the inside diameter of the wet well. A four
or six bolt hole pattern shall accommodate the mounting of a cover wit at least 1/4"
in diameter 300 series stainless steel fasteners. Non-corroding stainless steel
threaded inserts shall e fully encapsulated with non-continuous mat or chopped-strand glass
fiber reinforcement. The inserts shall have an offset tab to prevent stripping or
spinning out when removing and reinserting cover fasteners.
